1. Field of the Invention
This disclosure relates generally to gear trains, and, more particularly, to a logical third axle bicycle gear train for use with a detachable bicycle drive wheel.
2. Description of Related Art
Modern bicycles typically use a chain driven mechanism to transmit torque generated by the rider to the rear wheel of the bicycle. The bicycle operator places his feet on pedals, which are pivotally connected to crank arms. The crank arms are fastened to a crank core, which forms the center of a crank-core/crank-sprocket assembly. The crank sprocket drives a continuous drive chain, which transmits torque to a rear drive sprocket. The rear drive sprocket is connected to the rear drive wheel via a bicycle hub assembly, which typically includes a hub shell. The hub shell connects both the drive wheel and drive sprocket. The application of torque to the rear drive sprocket causes the hub shell to rotate on bearings internal to the hub assembly. In turn, rotation of the hub shell causes the rear drive wheel to rotate, propelling the bicycle forward.
Notwithstanding its prevalent use on bicycles, this configuration proves troublesome when removal of the rear wheel is required, because the rear drive sprocket is mounted on the same axle as the rear wheel. The drive chain must, therefore, be removed from the sprocket in order to free the rear wheel from the bicycle. This, in turn, requires slackening the drive chain by shifting into the lowest bicycle gear and manipulating the rear derailleur on the bicycle.
It is, therefore, desirable to enable removal of the rear bicycle drive wheel without requiring manipulation/removal of the bicycle drive chain.